Every medical site or book I've read firmly states that after the first two weeks of pregnancy, even the smallest amount of alcohol can give your baby Fetal Alcohol Syndrome. This is because with alcohol, the fetus drinks pretty much what you drink, but its organs haven't developed enough to process the alcohol safely. Plus, the fetus is tiny! Imagine you were a toddler and you drank a full glass of wine. They don't even let toddlers do that in France. Now imagine you're 1/8th the size of a toddler and you drink a full glass of wine! Not only would you pass out from blood poisoning, you'd probably suffer severe brain damage. In the first trimester, the fetus is smaller than an orange. It probably couldn't even handle a grape's worth of alcohol.
And yes, some lucky people drink a little wine during their pregnancy and nothing happens. Same with smoking and other risky behaviors. The point is, it's RISKY.
Keeping the dangers of alcohol in mind, how does cooking change the picture? Does alcohol cook away entirely because it has a lower boiling point than water? No. Here's a handy-dandy chart from the US Department of Agriculture:
|Alcohol Burn-off Chart|
|Preparation Method||Percent Retained|
|alcohol added to boiling liquid & removed from heat||85%|
|no heat, stored overnight||70%|
|baked, 25 minutes, alcohol not stirred into mixture||45%|
|Baked/simmered dishes with alcohol stirred into mixture:|
|15 minutes cooking time||40%|
|30 minutes cooking time||35%|
|1 hour cooking time||25%|
|1.5 hours cooking time||20%|
|2 hours cooking time||10%|
|2.5 hours cooking time||5%|